Also, an additional title means you can either leave two of your sons exalted hereditary titles OR that you can confer the lesser one onto your oldest son while you’re still alive.
Any connection between historical accuracy and RICHARD III is purely coincidental, but the real Duke of Buckingham was as high born as you could get without being in direct line to the throne, a descendant of Edward III by one of his sons and one of his daughters and thus a cousin of Richard III/Edward IV as well as the Lancastrians and several different ways. He was one of the richest nobles in the land from birth. His hatred of the royal house, or at least his resentment, was due to the same factor most people, Lancastrians and Yorkists, resented about Edward IV: his queen.
Stafford’s father and his grandfather were both killed fighting against the Yorkists (Richard’s family) leaving him a very wealthy orphan in his early teens. Wardships were always like blood in the water to nobles: the legal guardian of a wealthy orphan received a big percentage of their income, sometimes taking more than they were due and running the inheritance into the ground (think “parents of child stars”) but rarely leaving them better off than they found them. For starters in “How I learned to frigging detest Edward IV by Little Henry Stafford”, his wardship was assigned directly to the queen, Elizabeth Woodville Grey.
If you’re not familiar with her, she was lowborn by royal standards (her father was a minor nobleman) and the widow of a Lancastrian knight when she met Edward, then still fighting for the crown. By all accounts- including those by people who hated her- she was stunningly beautiful and even those who were in favor admitted she was greedy and selfish. She secretly married Edward when she was a widow he was still fighting for the crown and she kept him wrapped around her finger until he died. (Not completely I suppose: he did have mistresses and affairs and lots of bastards- but still managed to have a bunch of kids with her.)
The most hated thing about her was that she raised nepotism to new highs. Her family was fertile as alleycats (her parents had 15 children or thereabouts) and she married them all into the richest and most noble families; most infamous was when she married her brother John to the extremely wealthy Duchess of Norfolk when he was about 19 and she was almost 70. She also gave the wardships to any orphaned children of very wealthy families (including those orphaned due to being killed in battle or executed by her husband) to various of her relatives, and she took more of a role in public policy than most thought a queen- especially one who was queen only by virtue of a marriage that most thought never should have happened in the first place- should take.
When Stafford came to the age of maturity and she was about to lose control of his revenues, she decided to keep them in the family by betrothing him to a girl who happened to be her sister, Catherine Woodville. By all accounts it was a pretty miserable marriage, but he had no choice and it benefitted nobody but the Woodvilles. It did produce several children though.
Stafford remained loyal under Edward IV’s reign- after the Lancastrians were completely defeated there wasn’t a lot of reason not to be- but you can understand his resentment. Among other factors he had almost as good a claim to the throne as the Yorkists and to the remaining Lancastrians he was a much closer relative to Henry VI than Richard III was, and he was popular in regions of the country that didn’t like Richard. (Richard’s popularity was mostly in the north- which was odd, because he was the first Yorkist actually liked in York- they had gone Lancastrian during the wars.)
He was an indispensible ally to Richard immediately after Edward IV died and helped him literally seize custody of Edward V from his uncle Anthony Woodville. This he did probably because he hated the Woodvilles with a passion even if they were his close in-laws and wanted their power destroyed. After Edward V was illegitimized by the revelation Edward IV had not been free to marry when he wed Elizabeth Woodville Grey (he had been betrothed or plighted to another woman- a betrothal is less than a marriage but it’s more than an engagement, and this probably wasn’t even the only woman he’d done that with- Eddie had a tendency to promise women he’d marry them if they required it in order to sleep with him) which Stafford had to have relished in he seized his chance to break the Yorks once and for all by alligning with Henry Tudor.
There’s a lot of speculation by historians that if his rebellion had been successful and if Henry Tudor had won at that time (he ended up never setting foot in England due to storms and other problems) he probably wouldn’t have then rebelled against Tudor. He certainly had a much better claim to the throne than Tudor, who was a descendant of a bastard grandson of Edward III (true it was a bastard line that was later legitimized, but still a big stigma) and a bastard son of Henry V’s queen, while Stafford’s ancestry, though through daughters, was legitimate, and also Henry Tudor wasn’t a seasoned warrior and still had many enemies in England.
Anyway, he took a big risk and failed miserably and lost his head. By most accounts he did not make a dignified death. His estates however were allowed to pass to his children (i.e. they weren’t confiscated). After his death his widow married Henry VII’s uncle Jasper Tudor (one of the illegitimate sons of Queen Katherine de Valois), a man much older than she was, and then married a knight her own age when Jasper Tudor died.